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lib/Astro/Catalog/Item.pm  view on Meta::CPAN

            defined($self->coords)) {

        # We need to get a template FK5 SkyFrame to be able to convert
        # properly between RA/Dec and X/Y, but we can only do this if
        # we load Starlink::AST. So that we don't have a major dependency
        # on that module, load it here at runtime.
        eval {require Starlink::AST;};
        if ($@) {
            croak "Attempted to convert from RA/Dec to Y position and cannot load Starlink::AST. Error: $@";
        }
        my $template = new Starlink::AST::SkyFrame("System=FK5");
        my $wcs = $self->wcs;
        my $frameset = $wcs->FindFrame($template, "");
        unless (defined $frameset) {
            croak "Could not find FK5 SkyFrame to do RA/Dec to Y position translation";
        }
        my ($ra, $dec) = $self->coords->radec();
        my ($x, $y) = $frameset->Tran2(
            [$ra->radians],
            [$dec->radians],
            0);
        $self->{Y} = $y->[0];
    }

    return $self->{Y};
}

=item B<wcs>

Return (or set) the WCS associated with the star.

    $wcs = $star->wcs;
    $star->wcs($wcs);

The WCS is a C<Starlink::AST> object.

=cut

sub wcs {
    my $self = shift;
    if (@_) {
        my $wcs = shift;
        unless (defined $wcs) {
            $self->{WCS} = undef;
        }
        elsif (UNIVERSAL::isa($wcs, "Starlink::AST")) {
            $self->{WCS} = $wcs;
        }
    }
    return $self->{WCS};
}

=item B<comment>

Return (or set) a comment associated with the star

    $comment = $star->comment();
    $star->comment($comment_string);

The comment is propogated to the underlying coordinate
object (if one is present) if the comment is updated.

=cut

sub comment {
    my $self = shift;
    if (@_) {
        $self->{COMMENT} = shift;

        my $c = $self->coords;
        $c->comment($self->{COMMENT}) if defined $c;
    }
    return $self->{COMMENT};
}

=item B<spectype>

The spectral type of the Star.

    $spec = $star->spectype;

=cut

sub spectype {
    my $self = shift;
    if (@_) {
        $self->{SPECTYPE} = shift;
    }
    return $self->{SPECTYPE};
}

=item B<startype>

The type of star. Usually uses the Simbad abbreviation.
eg. '*' for a star, 'rG' for a Radio Galaxy.

    $type = $star->startype;

See also C<longstartype> for the expanded version of this type.

=cut

sub startype {
    my $self = shift;
    if (@_) {
        $self->{STARTYPE} = shift;
    }
    return $self->{STARTYPE};
}

=item B<longstartype>

The full description of the type of star. Usually uses the Simbad text.
If no text has been provided, a lookup will be performed using the
abbreviated C<startype>.

    $long = $star->longstartype;
    $star->longstartype("A variable star");

See also C<longstartype> for the expanded version of this type.